Meconium is excrement in the intestinal tract of a fetus. In a large majority of human fetuses, meconium is excreted shortly (e.g., with one or two days) after birth. However, approximately eight to sixteen percent of human fetuses discharge at least some meconium into the mother's amniotic sac prior to birth. Some fraction of those fetuses aspirate meconium into their lungs, and approximately one to two percent of those infants die from complications caused by the aspiration of meconium. Thus, the aspiration of meconium is a life threatening problem for approximately ten to twenty out of every ten thousand babies born.
If it is known that there is a significant amount of meconium in the amniotic fluid, it is possible to undertake measures to improve the baby's chances of survival. In particular, it is possible to intubate the baby's lungs immediately after birth so as to remove amniotic fluid in the baby's wind pipe and thereby remove as much meconium as possible from the baby's wind pipe and lungs.
In the prior art, there have been two primary techniques used to evaluate the meconium content of amniotic fluid. One, has been to use spectrophotometry. This technique requires a laboratory, uses expensive equipment, and is sufficiently expensive and difficult that it is not used routinely.
The second prior art technique is to simply visually inspect the amniotic fluid, often just by looking at the fluid which has been expelled during labor. If the fluid looks clear, the doctor concludes that there is probably little or no meconium present. If the fluid looks "thick" or dark, precautionary measures are taken to intubate the baby's lungs. Unfortunately, amniotic fluid that looks relatively clear upon casual inspection may contain significant amounts of meconium. Nevertheless, this technique is the main one used routinely in the prior art, because it is inexpensive, even though it is insufficiently accurate to provide a reliable indication of meconium content.
The present invention provides a simple method of evaluating meconium content which is both very inexpensive and simple to use.